Omphalocele and laparoschisis are congenital anomalies characterized by a defect in closing the abdominal wall of the fetus, associated with exteriorization (herniation) of part of its abdominal viscera. These malformations require specialized care at birth and surgery to reintegrate the viscera into the abdomen. The prognosis is favorable in the majority of cases.

Definition

Omphalocele and laparoschisis are congenital anomalies characterized by a failure to close the abdominal wall of the fetus.

The omphalocele is characterized by a more or less wide opening in the abdominal wall, centered on the umbilical cord, through which part of the intestine and sometimes the liver emerge from the abdominal cavity, forming what is called a hernia. When the defect in closing the wall is important, this hernia can contain almost all of the digestive tract and the liver.

The exteriorized viscera are protected by a “bag” comprising a layer of amniotic membrane and a layer of peritoneal membrane.

Frequently, omphalocele is associated with other birth defects:

• most often heart defects,
• genitourinary or cerebral abnormalities,
• gastrointestinal atresia (i.e. partial or total obstruction) …

In fetuses with laparoschisis, the abdominal wall defect is located to the right of the navel. It is accompanied by a hernia of the small intestine and in some cases of other viscera (colon, stomach, more rarely bladder and ovaries).

The intestine, which is not covered with a protective membrane, floats directly in the amniotic fluid, the urinary components present in this fluid being responsible for inflammatory lesions. Various intestinal abnormalities can occur: modifications and thickening of the intestinal wall, atresias, etc.

Typically, there are no other associated malformations.

Causes

No specific cause for the defective closure of the abdominal wall is demonstrated when omphalocele or laparoschisis appear in isolation.

However, in about a third to half of cases, the omphalocele is part of a polymalformative syndrome, most often associated with trisomy 18 (one extra chromosome 18), but also with other chromosomal abnormalities such as trisomy 13 or 21, monosomy X (a single X chromosome instead of a pair of sex chromosomes) or triploidy (presence of an extra batch of chromosomes). About once in 10 the syndrome results from a localized gene defect (especially omphalocele associated with Wiedemann-Beckwith syndrome). 

Diagnostic

These two malformations can be demonstrated on ultrasound from the first trimester of pregnancy, generally allowing prenatal diagnosis.

Persons concerned

Epidemiological data vary between studies.

According to Public Health France, in the six French registers of congenital anomalies, over the period 2011 – 2015, omphalocele affected between 3,8 and 6,1 births out of 10 and laparoschisis between 000 and 1,7 births in 3,6.

Risk factors

Late pregnancy (after 35 years) or through in vitro fertilization increases the risk of omphalocele.

Environmental risk factors such as maternal tobacco or cocaine use may be involved in laparoschisis.

Antenatal therapeutic attitude

To avoid excessive lesions of the intestine in fetuses with laparoschisis, it is possible to perform amnio-infusions (administration of physiological serum into the amniotic cavity) during the third trimester of pregnancy.

For these two conditions, specialized care by a multidisciplinary team comprising specialists in pediatric surgery and neonatal resuscitation must be organized from birth in order to avoid major infectious risks and intestinal suffering, including outcome would be fatal.

An induced delivery is usually scheduled to facilitate management. For omphalocele, vaginal delivery is generally preferred. Cesarean section is often preferred for laparoschisis. 

surgery

The surgical management of infants with omphalocele or laparoschisis aims to reintegrate the organs into the abdominal cavity and close the opening in the wall. It starts soon after birth. Different techniques are used to limit the risk of infection.

The abdominal cavity that remains empty during pregnancy is not always large enough to accommodate the herniated organs and it can be difficult to close it, especially when a small baby has a large omphalocele. It is then necessary to proceed with a gradual reintegration spread over several days, or even several weeks. Temporary solutions are adopted to protect the viscera.

Evolution and prognosis

Infectious and surgical complications cannot always be avoided and remain a concern, especially in the event of a long hospital stay.

Omphalocèle

Reintegration into an undersized abdominal cavity of a large omphalocele can cause respiratory distress in the baby. 

For the rest, the prognosis of isolated omphalocele is rather favorable, with a rapid resumption of oral feeding and the survival to one year of a very large majority of babies, who will grow normally. In the event of associated malformations, the prognosis is much worse with a variable mortality rate, which reaches 100% in certain syndromes.

Laparoschisis

In the absence of complications, the prognosis of laparoschisis is essentially linked to the functional quality of the intestine. It may take several weeks for motor skills and intestinal absorption to recover. Parenteral nutrition (by infusion) must therefore be implemented. 

Nine out of ten babies are alive after one year and for the vast majority, there will be no consequences in everyday life.